Thermoelectric devices have been used for many years for specific applications where the simplicity of design warrants their use despite a low energy conversion efficiency.
The voltage produced by a thermoelectric device depends on the Seebeck voltage of the dissimilar metals used. Seebeck voltages are higher for some semiconductor materials especially n-type and p-type elements made primarily of mixtures bismuth, tellurium, and antimony.
To compete with more traditional forms of heat to electricity conversion thermoelectric devices must be as efficient as possible. A preferred means to achieve such high efficiency is to arrange the thermoelectric element in a circle with only a very small region used to extract the energy produced by the thermoelectric elements. Patent PCT/US97/07922 to Schroeder discloses such a circular arrangement. Art teaching in this case focused on 3 means to extract energy for the high current in the ring of elements: 1—a vibrating mechanical switch; 2—a Hall effect generator and; 3—a Colpits oscillator. Coatings of hot and cold elements of the thermoelectric device are claimed for selenium, tellurium and antimony among others but not for mixtures of these elements.
U.S. Pat. No. 6,222,242 to Konishi, et al., discloses semiconductor material of the formula AB.sub.2, X.sub.4 where A is one of or a mixture of Pb, Sn, or Ge, B is one of or a mixture of Bi and Sb and X is one of or a mixture of Te and Se. These represent Pb, Sn or Ge doped bismuth telluride.
U.S. Pat. No. 6,274,802 to Fukuda, describes a sintering method of making semiconductor material whose principle components include bismuth, tellurium and selenium and antimony.
U.S. Pat. No. 6,340,787 to Simeray discloses a thermoelectric component of bismuth doped with antimony and bismuth tellurium doped selenium wherein said component is arranged into a rod. Very low voltages are converted using a self-oscillating circuit.
U.S. Pat. No. 6,172,427 describes the use of a thermoelectric device on the exhaust portion of a combustion-based car using electrically driven wheel wherein excess heat energy is converted to electric power for the vehicle.
It is a purpose if this invention to provide improved efficiency for the conversion of heat energy to electrical energy by making use of n-doped and p-doped semiconductors attached to metal heat-conducting elements in a circular arrangement of thermoelectric components.
It is a further purpose of this invention to provide a high efficiency of transmission of energy contained in a thermoelectric ring to AC current at desired voltages utilizing a make-before-break high frequency switching circuit.
Another purpose of this invention is to improve the efficiency of said thermoelectric device by combining it with a chiller. Excess heat from the thermoelectric is transferred to the chiller where it is converted to cold air or liquid. The cold air or liquid is then transported to the cold fins of the thermoelectric device where by lowering the temperature of the cold fins increases the voltage for a given heating arrangement.
It is also a purpose of this invention to provide an efficient device to convert a variety of heat sources to electricity.